Nozzle



fr. w. BURNAM NozzLE Filed June 1; 1942 Aug. 21, 1945.

Patented Aug. 21, 1945 UNITED STATES PATENT lOFFICE 8 Claims.

This invention relates to a nozzle of the type intended for creating afog of liquid particles. One of the objects of the present invention isto provide a nozzle adapted for use on low pressure iiuid sources, asfor example in homes andfactories, which nozzle is capable ofextinguishing or controlling res and Afor combating incendiary bombs. l

The nozzle of thev present invention employs a limited volume of waterand has the advantage that it is capable of quickly extinguishing largeareas of fires adjacent an incendiary bomb nre without the necessity ofusing a solid or straight water stream for such purpose. The nozzle ofthe present invention thereby avoids the danger which accompanies theapplication of a straight or solid stream of water to a magnesium fire.The nozzle of the present invention produces a water spray of fog inwhich the water particles .are distributed substantially uniformlythroughout the spray pattern infront of the nozzle, avoiding thepossibility of pockets of combustible gases accumulating within thewater spray. With the nozzle of the present invention there is,therefore, no danger to the operator of explosive backflres.

The nozzle of the present invention is furthermore so designed as toproject the water a considerable distance in advance of the nozzle, evenwhen the nozzle is operating at low pressures, and at the same time iscapable of spreading out the water sufficiently to provide a. watercurtain between the operator and the fire which protects the operatoragainst excessive heat.

The foregoing advantages of the nozzle of the present invention resultfrom certain discoveries made relative to the action of lmpinging iiuidjets. When a nozzle is provided with orifices so arranged. as to formjets which impinge one against the other at a proper position in advanceof the nozzle, the fluid may be broken up into a fog or spray in amanner best described, for example, in the United States Patent toJones, No. 2,235,258. Previous to the present invention, the impingingjet type of nozzle is operated satisfactorily only where the fluidpressure available for application of the nozzle is higher thanpressures normally. available in homes. The nozzle of the presentinvention utilizes certain `discoveries made concerning the action ofimpinging iiuid jets where the impinging jets are produced by orifices4of relatively` different diameters. By employing orifices of relativelydifferent-diameters in an impinging jet nozzle, I have discovered, amongother things, that the nozzle may be made to operate satisfactorily atgreatly reduced pressures,. while at the same time the projection of`the spray created by the nozzle may be very materially increased whilestill retalningthe property of properly subdividing the water or otherfluid. The discoveries made, together with various additional advantagesthereof, will be more fully understood from a description of a preferredfrom or example of a nozzle embodying the invention. I have, therefore,described a preferred example of such nozzle in connection with theaccompanying drawing,.in which Figure 1 is a side elevation.

Figure 2 is an end view.

Figure 3 is a section.

Figure 4 is an exploded view. Figure 5 is a perspective illustrating theaction of the nozzle at extremely low pressures.

Referring to the drawing, the nozzle comprises a body having a portionprovided with cylindrical side walls 2 andwith an end wall 3, having anannular V-shaped depression 4 providing inner and outer angled surfaces.A circumferential series of orifices 5 is provided in the outer angledsurface of the end wall and a like number of orifices 6 is provided inthe inner angledsurface. The orifices 5 and 6 are arranged in pairs sothat the jets of w'ater or other fluid, which in operation of the nozzleare emitted from the orifices, are capable of' impinging one against theother.

.The body of .the nozzle is also provided with an enlarged portion 'lintended for forming a socket,` by means of which the nozzle may beattached to a threaded nipple or fitting, a shoul- V der 8 thereby beingformed between the portions 2 and I of the body. Frusto-conical shapedmember 9 is, provided having a flange on its base resting against .theshoulder 8 and having an aperture I0 at its apex to permit passage ofwater 11s, in turn, engaged by a coiled wire I4 which operates as a.coupling thread for attaching the nozzle to a threaded fitting. Thecoiled wire i4 is held in place by a, spring washer l5.

The lower edge of the socket portion 1 is turned in slightly to retainthe milled wire il in position Within the socket.

The action of the nozzle of the present invention is materially governedby the relative diameters of the orifices 5 and 6. The effect producedin the nozzle of the present invention by the use of orifices E ofrelatively smaller diameter than the diameter of the orifices 5 may beillustrated by the following data: When the diameter of the orifices 5and 6 was made identical (i. e., both drilled with a No. 60 drill), itwas found that the nozzle did not properly break up water unless thepressure on the nozzle was at least 30 pounds per square inch and theprojection of the water varied from 12 to 17 feet as the pressure on thenozzle varied from 35 to 100 pounds per square inch. When a nozzle wasconstructed using a No. 56 drill for the orifices 5 and a No. 60 drillfor the orifices 6, it was found that the nozzle would operate to breakup the water at pressures as low as pounds per square inch, and wouldproject the water from 12 to 19 feet asthe pressure on the nozzle variedfrom to 100 pounds per square y inch. When the orices 5 were formed by aNo.

may be employed. For best operation, the number of pairs of orifices,however, can not be arbitrarily selected, but the number to be employedshould be such that the water spray produced by each individual pair oforifices properly meets and combines with the spray produced by eachadjacent pair of orifices. If less than the necessary number of pairs oforifices for this purpose is employed there may be channels in the sprayprojected by the nozzle which are not occupied by water spray, whereasif a larger number is employed the sprays from adjacent pairs mayintermingle to the extent of producing streams ofwater'within the spraypattern. Whether or not the proper number in spacing of the pairs oforifices has been adopted can be determined by operating the nozzle atextremely low pressures. At extremely low pressures the impinging jetsin place of breaking the water into fog particles immediately adjacentthe point of impingement form small water leaflets, as indicated at i8in Figure 5. The water leaflets formed by adjacent pairs of orificesshould just meet at their points of maximum width. When this conditionis fulfilled, the

nozzle when operated at higher pressures acts as a single unit forming aspray in which the water is substantially uniformly distributed and inwhich y there are no channels unoccupied by water parwas projected from21 to 30 feet as the pressure applied to the nozzle varied from 20 to100 pounds per square inch. Thus, by changing the relative size of theorifices 5 and S, the minimum pressure for satisfactory operation wasreduced from to less than 5 pounds per square inch, whereas theprojection of the Wat-er by the nozzle was increased from 17 to 30 feetwhen the pressure on thenozzle was 100 pounds per square inch. Furtherirnprovement by further change in the relative size of the orifices 5and 6 might be expected from the foregoing tabulation, but in practice Ido not find it possible to achieve any substantial improvement. When thearea of the outer larger orifices 5 becomes greater than about threetimes the area of the smaller inner orifices 6, the Volume of waterprojected from the inner orifices to impinge against the Volumeprojected from the outer orifices becomes too small for the nozzle toany longer properly break up or fog the water emitted from the nozzle.

I believe the explanation for the improvement effected in the action ofnozzles by the present invention to be as follows:

When' the volume of water emitted from the inner orifices 6 is less thanthe volume of water emitted from the outer orifices 5, only a portion ofthe volume of water emitted from the outer orifices is broken up into afog of water particles at the points 5a of impingement of the waterjets.

-idly'extinguishing fires started in the neighborhood of an 'incendiarybomb, while at the same time the spray from the nozzle may be applieddirectly to the magnesium fire itself for accelerating and controllingthe burning of the magnesium fire. Furthermore, because of the distanceto which the water may be projected by the nozzle of the presentinvention, the operator may stand at a distance from the incendiary orsurrounding fires and be free from danger. The nozzle of the presentinvention has a further advantage in that the water spray created by thenozzle is effective for protecting the operator from the heat of thefire and enables the operator to approach res and fight fires safely atpositions where without As indicated in the perspective view, Figure 5,the

remainder of the water from the outer jets 5 is deflected, as indicatedat I6, and these deflected portions of the water from the outer orifices5 undergo-What may be considered as a secondary impingement at theaxis'of the nozzle, as indicated at l1, which secondary impingementserves to in.- sure further breaking up of the water, as well as itsprojection forward the result of this action being to extend thedistance to which the water is projected by the nozzle. In theparticular nozzle shown, four pair of orifices 5 and 6 are ar- .rangedcircumferentially of the nozzle, but for other specific designs agreater or lesser number the heat protection qualities provided by thenozzle the operator might otherwise be unable to remain.

The present invention, of course, is not limited to the specific form ofnozzle herein shown, but the discoveries of the present invention arecapable of being utilized in a wide variety of no'zzles, and theinvention includes all such modifications and changes as come within thescope of the appended claims.

I claim:

1. A fog nozzle, comprising a body having a plurality of relativelylarge orifices having intersecting axes and a plurality of relativelysmaller orifices having axes which intersect the axes of the relativelylarger orifices at points closer to the nozzle body than the point ofintersection on the axes of the. relatively larger orifices with eachother.

2. A fog nozzle, comprising a. nozzle body having a circular series ofrelatively large orifices positioned on axes which intersect, orificesof relatively small diameter corresponding to each of the relativelylarge oriilces haviugaxes intersecting the axes of the relatively larger.oriiices at a point closer to the nozzle body than the points ofintersection yof the axes of the larger orifices with each other.

3. A fog nozzle, comprising a body having an end face with an annulararcuate-shaped groove,

a series of oriiices in the outer -wall of saidgroove of( relativelylarge diameter and a series of orifices in the inner wall of said grooveof relatively small .diameter in position to form lets which impingewith the jets produced with the larger'orices. y A 1. Afog'nozzlacomprising a nozzle body-having a plurality of pairs oforifices arranged circumferentially on the face of the nozzle, each pairof oriiices including an outer oriilce of relatively large diameter andan inner orifice of relatively small diameter, such pairs of oriilcesbeing formed on axes which intersect shortly in advance of the orifices.the pairs oi-oriilces being arranged so that the liquid emitted from therelatively larger orifices undergoes av secondary imliquid spray bylioint action of the several pairs of orices. j

.v 6. A fog nozzle, comprising a body having a plurality of pairs of.orifices arranged in a cir\ cular series, each pair of orificesincluding an orifice of relatively largediameterand an orifice ofrelatively small diameter positioned on intersecting axes, the orcesbeing arranged so that the liquid emitted from lthe relatively largerorifices which is notbroken up by the imp'ingement with the liquid fromthe relatively smaller oriices undergoes a secondary'impingement at apoint inn advance of the nozzle body, the circular spacing of the pairsof orifices being such that the plurality of pairs of oriiices cooperateto pro-'A duce a single'fog' pattern. Y

. 7. A fog nozzlecomprislng a body having a plurality of pairs oforifices, each pair of orices being adapted to form impingingjets andincluding an orifice of relatively large diameter and an orificel ofrelatively small diameter, av frustoconical shaped memberpositionedwithin thel nozzle body, and a screening member across-the Abase of said frusto-conical member.

8. A fog nozzle, comprising a body having a4 socket portion and a nozzleportion, a frustoconical member within the body and extending into thenozzle portion. the end wall oi' said body portion being provided with acircular vseries oi pairs of oriices adapted to'formimpinging iets, theouter orices of each pair being of relatively 30 larger diameter thaninner princes.

"'rnoirpson w. nunmal.

